The invention relates to a scheduling system and a work order scheduling protocol for such an agent-based scheduling system.
Current production scheduling systems based on centralized and complex algorithms usually provide a pre-defined list of choices that permit to customize and tune their general-purpose behavior to the needs of a user, typically a company. Such prior art schedulers generally do not permit an easy definition of new criteria by the end users and/or taking into account new constraints.
In order to be truly effective, production scheduling systems must be reactive and highly configurable to adapt to different on-going manufacturing scenarios.
A second desirable feature implies the possibility of easily customizing the scheduling rules, by adapting them to different, changing constraints and objectives.
Known scheduling and manufacturing execution systems consider two decision makers, one for the scheduling activity and one for the manufacturing execution and control activity, that cooperate in a more or less tight way. This allows forecasting of problems in the plant (e.g. machine breakdowns, machine bottlenecks, etc.) and allows the scheduler to react for limiting such problems or to suggest modification of the plant layout/configuration. Such a process requires a number of iterations including scheduling decisions and plant controlling decision with reciprocal feedback before reaching a satisfying solution. However, the quality of solutions that these scheduling architectures can obtain are not satisfying due to the long interaction process they require and the impossibility of making a decision that lead straight to the optimal choice for both the plant configuration and the production schedule.